Digital content delivery system

Abstract

A digital content distribution system ( 1 ) is composed of a right management server ( 100 ) and a user terminal ( 110 ) which are connected via a transmission line ( 120 ). The right management server ( 100 ) is made up of: a license data generating unit ( 304 ) which issues license data (usage right information) ( 1700 ) indicating a usage rule of content that is a digital copyrighted work to the user terminal ( 110 ); and an access condition setting unit ( 305 ) which notifies the user terminal ( 110 ) of update information (access condition) regarding necessity of updating the license data ( 1700 ) issued to the user terminal ( 110 ). The user terminal ( 110 ) is made up of: a content DB ( 701 ) which stores content; a license data DB ( 702 ) which stores the license data ( 1700 ) issued by the license data generating unit ( 304 ); a content reproducing unit ( 710 ) which uses the content stored in the content DB ( 701 ) in accordance with the usage rule indicated by the license data ( 1700 ) stored in the license data DB ( 702 ); and a license data upgrading unit ( 706 ) which requests the right management server ( 100 ) to update the license data ( 1700 ) stored in the license data DB ( 702 ) in accordance with the access condition notified by the access condition setting unit ( 305 ).

1 . A digital content distribution system comprising a right management server and a user terminal which are connected via a transmission line, 
 wherein said right management server includes:    a usage right information issuing unit operable to issue usage right information indicating a usage rule of content which is a digital copyrighted work to said user terminal; and    an update information notifying unit operable to notify said user terminal of update information regarding necessity of updating the usage right information issued to said user terminal, and    said user terminal includes:    a content storing unit operable to store the content;    a usage right information storing unit operable to store the usage right information issued by said usage right information issuing unit;    a using unit operable to use the content stored in said content storing unit in accordance with the usage rule indicated by the usage right information stored in said usage right information storing unit; and    an update requesting unit operable to request said right management server to update the usage right information stored in said usage right information storing unit, in accordance with the update information notified by said update information notifying unit.    
     
     
         2 . The digital content distribution system according to  claim 1 , 
 wherein said update information notifying unit is operable to notify said user terminal of the update information by including the update information in the usage right information issued by said usage right information issuing unit.    
     
     
         3 . The digital content distribution system according to  claim 2 , 
 wherein the update information includes information regarding a timing at which said user terminal should access said right management server, and    said update requesting unit is operable to access said right management server at the timing indicated by the update information and to request said right management server to update the usage right information.    
     
     
         4 . The digital content distribution system according to  claim 2 , 
 wherein the update information includes information regarding a frequency at which said user terminal should access said right management server, and    said update requesting unit is operable to access said right management server at the frequency indicated by the update information and to request said right management server to update the usage right information.    
     
     
         5 . The digital content distribution system according to  claim 2 , 
 wherein the update information includes a flag showing whether or not said user terminal should access said right management server, and    said update requesting unit is operable to access said right management server in accordance with the flag and to request said right management server to update the usage right information.    
     
     
         6 . The digital content distribution system according to  claim 1 , 
 wherein the usage right information includes an identifier to identify itself, and    the update information includes the identifier of the usage right information which is an object to be updated.    
     
     
         7 . The digital content distribution system according to  claim 6 , comprising a plurality of user terminals, 
 wherein said update information notifying unit is operable to specify, for each user terminal, the usage right information which is the object to be updated among sets of the usage right information held by said user terminal, to create the update information including the identifier of the specified usage right information, and to notify said user terminal of the created update information.    
     
     
         8 . The digital content distribution system according to  claim 6 , comprising a plurality of user terminals, 
 wherein said update information notifying unit is operable to specify, for each user terminal, the usage right information which is the object to be updated among sets of the usage right information held by all of said plurality of user terminals, to create the update information including the identifier of the specified usage right information, and to notify said user terminal of the created update information.    
     
     
         9 . The digital content distribution system according to  claim 1 , 
 wherein said right management server further includes    an update data transmitting unit operable to transmit, to said user terminal, data for usage right information update that is used for updating the usage right information held by said user terminal to latest usage right information when receiving a request to update the usage right information from said user terminal,    said user terminal further includes    an updating unit operable to receive the data for usage right information update that is transmitted from said right management server, to read the usage right information corresponding to the received data for usage right information update from said usage right information storing unit, and to update the read usage right information, and    said using unit is operable to use the content stored in said content storing unit in accordance with the usage rule indicated by the updated usage right information.    
     
     
         10 . The digital content distribution system according to  claim 9 , 
 wherein the usage right information includes an identifier to identify itself,    said update requesting unit is operable to request an update by notifying said right management server of the identifier of the usage right information which is to be an object of the update, and    said update data transmitting unit is operable to transmit, to said user terminal, the data for usage right information update that is used for updating the usage right information identified by the identifier notified by said update requesting unit to the latest usage right information.    
     
     
         11 . The digital content distribution system according to  claim 10 , 
 wherein said update requesting unit is further operable to request the update by notifying said right management server of the usage rule of the usage right information together with the identifier of the usage right information.    
     
     
         12 . The digital content distribution system according to  claim 9 , 
 wherein said update requesting unit is operable to request an update by transmitting the usage right information which is an object of the update to said right management server, and    said update data transmitting unit is operable to transmit, to said user terminal, the data for usage right information update that is used for updating the usage right information transmitted from said update requesting unit to the latest usage right information.    
     
     
         13 . The digital content distribution system according to  claim 9 , 
 wherein the usage right information includes an identifier to identify itself,    the data for usage right information update includes the identifier of the usage right information which is an object to be updated and data indicating details of the update, and    said updating unit is operable to update the usage right information on the basis of the identifier and the data indicating the details of the update that are included in the data for usage right information update.    
     
     
         14 . The digital content distribution system according to  claim 9 , 
 wherein the usage right information includes an identifier to identify itself,    the data for usage right information update includes the identifier of the usage right information which is an object to be updated and information indicating an updated usage rule, and    said updating unit is operable to read, from said usage right information storing unit, the usage right information identified by the identifier included in the data for usage right information update, and to update the usage right information by replacing the usage rule of the read usage right information with the updated usage rule included in the data for usage right information update.    
     
     
         15 . The digital content distribution system according to  claim 9 , 
 wherein the data for usage right information update includes updated usage right information, and    said updating unit is operable to read, from said usage right information storing unit, the usage right information corresponding to the updated usage right information included in the data for usage right information update, and to update the usage right information by replacing the read usage right information with the updated usage right information included in the data for usage right information update.    
     
     
         16 . The digital content distribution system according to  claim 9 , 
 wherein the usage right information includes an identifier to identify itself,    the data for usage right information update includes the identifier of the usage right information which is an object to be updated and additional data which should be linked to the usage right information that is the object to be updated, and    said updating unit is operable to read, from said usage right information storing unit, the usage right information identified by the identifier included in the data for usage right information update, and to update the usage right information by linking the additional data to the read usage right information.    
     
     
         17 . The digital content distribution system according to  claim 9 , 
 wherein the usage right information includes an identifier to identify itself,    the data for usage right information update includes the identifier of the usage right information which is an object to be updated and additional license information indicating a usage rule to be added, and    said updating unit is operable to read, from said usage right information storing unit, the usage right information identified by the identifier included in the data for usage right information update, and to update the usage right information by adding the usage rule indicated by the additional license information included in the data for usage right information update to the usage rule indicated by the read usage right information.    
     
     
         18 . The digital content distribution system according to  claim 9 , 
 wherein said usage right information issuing unit is operable to affix a digital signature to the usage right information, and to transmit the usage right information together with the obtained signature text to said user terminal, and    said update data transmitting unit is operable to affix a digital signature to the data for usage right information update, and to transmit the data for usage right information update together with the obtained signature text to said user terminal.    
     
     
         19 . The digital content distribution system according to  claim 1 , 
 wherein said update requesting unit is operable to obtain, from said right management server, data for usage right information update that is used for updating the usage right information stored in said usage right information storing unit when requesting said right management server for an update.    
     
     
         20 . A right management server of a digital distribution system which comprises said right management server and a user terminal that are connected via a transmission line, 
 wherein said right management server includes:    a usage right information issuing unit operable to issue usage right information indicating a usage rule of content which is a digital copyrighted work to said user terminal;    an update information notifying unit operable to notify said user terminal of update information regarding necessity of updating the usage right information issued to said user terminal; and    an update data transmitting unit operable to transmit, to said user terminal, data for usage right information update that is used for updating the usage right information held by said user terminal to latest usage right information when receiving a request to update the usage right information from said user terminal.    
     
     
         21 . A user terminal of a digital distribution system which comprises a right management server and said user terminal that are connected via a transmission line, 
 wherein said user terminal includes:    a content storing unit operable to store content which is a digital copyrighted work;    a usage right information storing unit operable to store usage right information issued by said right management server;    a using unit operable to use the content stored in said content storing unit in accordance with a usage rule indicated by the usage right information stored in said usage right information storing unit;    an update requesting unit operable to request said right management server to update the usage right information stored in said usage right information storing unit, in accordance with update information notified by said right management server; and    an updating unit operable to receive data for usage right information update that is transmitted from said right management server, to read the usage right information corresponding to the received data for usage right information update from said usage right information storing unit, and to update the read usage right information, and    said using unit is operable to use the content stored in said content storing unit in accordance with a usage rule indicated by the updated usage right information.    
     
     
         22 . A right management method used by a digital content distribution system comprising a right management server and a user terminal which are connected via a transmission line, said right management method comprising: 
 a usage right information issuing step of issuing usage right information indicating a usage rule of content which is a digital copyrighted work to the user terminal;    an update information notifying step of notifying the user terminal of update information regarding necessity of updating the usage right information issued to the user terminal; and    an update data transmitting step of transmitting, to the user terminal, data for usage right information update that is used for updating the usage right information held by the user terminal to latest usage right information when receiving a request to update the usage right information from the user terminal.    
     
     
         23 . A content usage method used by a digital content distribution system comprising a right management server and a user terminal which are connected via a transmission line, said content usage method comprising: 
 a usage right information obtaining step of obtaining usage right information issued by the right management server;    a using step of using content which is a digital copyrighted work, in accordance with a usage rule indicated by the obtained usage right information;    an update requesting step of requesting the right management server to update the usage right information, in accordance with update information notified by the right management server; and    an updating step of receiving data for usage right information update that is transmitted from the right management server and of updating the usage right information corresponding to the received data for usage right information update,    wherein in said using step, the content is used in accordance with a usage rule indicated by the updated usage right information.    
     
     
         24 . A program for a right management server of a digital content distribution system comprising said right management server and a user terminal which are connected via a transmission line, said program causing a computer to execute said steps of the right management method described in  claim 22 .  
     
     
         25 . A program for a user terminal of a digital content distribution system comprising a right management server and said user terminal which are connected via a transmission line, said program causing a computer to execute said steps of the content usage method described in  claim 23.